Flux and 3.5 use 100% of my GPU

It just can't be. I have a pc with a 4090 and Intel core I9, how is it possible that I can't generate a simple image with flux or SD3.5?! The pc freezes and does not generate anything, the memory runs out and the GPU works at maximum but without producing anything. It's unnerving to see people create incredible works with less powerful pc. How to solve?